dtpcrm (version 0.1.1)

stop_for_excess_toxicity_logistic: Stopping for excess toxicity - Logistic method

Description

This is a function for use with applied_crm for the stop_func argument. The rule will suggest stopping in the scenario that the probability of toxicity being greater than a specifed value at a defined dose is greater than some further specified certainty value.

Usage

stop_for_excess_toxicity_logistic(x, tox_lim, prob_cert, dose = 1,
    nsamps = 10^6, suppress_dose = TRUE)

Arguments

x

An object of class 'mtd'.

tox_lim

A numeric; specifying the value for which the estimated toxicity at the selcted dose is not to exceed.

prob_cert

A numeric; specifying the probability value to be used when assessing the certainty required that toxicty at the specificed dose exceeds tox_lim.

dose

An integer; the dose to be assessed.

nsamps

Number of samples used for beta in the underlying normal sampling of beta.

suppress_dose

A logical value indicating if the MTD should be set to NA if trial should stop.

Details

This function is an example of a possible stopping function to be used with applied_crm, it will modifiy the 'mtd' class object produced by applied_crm to include a logical value under the name 'stop' indicating whether or not the trial should stop. The package dtpcrm contains a few of these functions for possible use with applied_crm.

Examples

# NOT RUN {
prior  <- c(0.1, 0.3, 0.5)
target <- 0.2
tox    <- c(0, 0, 1, 0, 1, 1)
level  <- c(1, 1, 1, 2, 2, 2)

stop_rule <- function(x){
  x <- stop_for_excess_toxicity_logistic(x, tox_lim = 0.25, prob_cert = 0.85)
}

crm <- applied_crm(prior, target, tox, level, no_skip_esc = TRUE, no_skip_deesc = TRUE,
                   global_coherent_esc = TRUE, stop_func = stop_rule)

# }